Flying boat



FLYING BOAT Fiied March 24, 1924 2 sheets-sheet 1 Patented st. 19, 1926.

UNiTan STATES PATENT FLYING Boar.

Application tiled March 24, 1924, Serial No. 701,495, and in GermanyJune 2l, 1920.

This invention relates to hydroaeroplanes and particularly to flyingboats. 4

, The object of the inyention generally is to increase the lateralstability .of the craft 5 while floating and taxying, to facilitate andexpedite the operation of starting and emerging from the water and toreduce the power required for taking ott". A further object of theinvention is a flying boat in l0 which the displacement ofthe boat maybe substantially reduced as compared with prior flying boats with whichI am familiar. V To these ends l have 'devised a flying boat including aspecial arrangement of central l5 boat hull structure and sidedisplacement oats, whereby the frontal and frictional resistances of t eparts Vin the water are substantially reduced at starting and thebringing of the craft to the hydroplaning position may be quickly andeasily effected, thereby rendering available an addition of energy or.

power for the taking ott operation and substantially reducing thetake-ott distance and time as compared with prior lyin boats.

According to my invention the ying boat is provided with twodisplacement and hydroplaning floats substantially centrally arranged onopposite sides of the central boat hull and in comparatively closeproximity thereto, the boat extending below the level of the bottoms ofthe displacement floats. A. great and positive metacentric height atrest and while taxying is thereby secured for the craft, together withan increased dynamic lifting effect and reduction of resistances atstarting. The displacement loats exert a. positive lifting eiect on thecraft and after overcoming the critical 'speed they are graduallydetached from the water, emerg-l ing therefrom prior to the emergence ofthe boat hull, the. complete take-oil' of the boat being therebyexpedited and facilitated.

In consequence of the arrangement of the two lateral floats close to theboat. the dimensions of the llying boat regarding its displacement canbe considerably reduced as the lateral floats support at the state ofrestand at the starting, a considerable part of the load. If the boat isrunning, the load resting upon the floats, diminishes at increasingspeed and, in accordance w1th the increasing lifting power, this reducedload can now be easily carried by the flying boat of smaller dimensions.It is, however, necessary, to reduce with increasing relieving of thefloats the frontal and frictional re sisntances of the same in thewater. With this object in view, the boat is constructed in such mannerthat, in the course of the starting from the water, the boat graduallybecomes self-carrying, the floats reducing the resistances by graduallifting.

The central arrangement of loats in close' proximity to the boatcombines the advantages of a dying boat with the advantages of afloat-flying` machine.

For a better understanding of the invention reference may be had to theaccompanymg drawings forming a part of this application vvherein- Fig. lshows the dying boat in. front elevation, c

Fig. 2 shows the dying boat as land-dying machine, f

And Figs. 3 and 4 are side elevations of a flying boat embodying amodified form of my invention.

The drawing (Fig. l) shows by way of example a twin-engined monoplane.'The hull 1-of this machine is constructed boatlike. Ateither side of thehull a float 2, 3 is arranged, connected with the boat hy hinged struts4. The supporting stays 5, 6, extending towards the supporting planes,are attached to the strutsA 4. The floats 2 and are displacement andhydroplaning tloats and are substantially centrally disposed and incomparatively close' proximity to the boat hull 1.

For the floats 2, 3 on the horizontal struts 4 wheels 7 8 may besubstituted (Fig. 2) so that the flying boat can be used as a landflying machine, .the struts 4 being arranged as horizontal axles, asshown.

The process ot the combined action of the boat and its lateral oats istaking place according to the following principles: The two floatsarranged at the sides of the hull are comparatively small. Thereforethey possess comparatively little weight and meetwith littleair-resistance. By the coordination of the two loats to the flying boat,the latter can be of smaller dimensions, so that its size need not beany bigger than the requirements for accommodationy necessitate.

At the state of rest the floats produce a positive metacentric height sothat the machine does not take an inclination as is the case. withflying boats of known types. At increasing speed the planes begin tocarry so that the boat and the floats will gradually emerge from thewater. In consequence of the different immersion of the Heats 'withregard to the boat, the lloats Will get out of the Water much sooner,this resultingin a reducing of the resistance in the water, be-

ln order to attain these advantages, the

@oats may be situated at a different height from the boat, or they maybe removed into the directionof the longitudinal axis of the flyingmachine, as for example illustrated in Figs. 3 and ll of the drawing sothat because of the inclination of the llying machine at the starting,they leave the Water prior to the boat.

ln l the supporting lloats 2 and 3 are indicated as having their planingbottoms disposed above the level of the bottom of the boat l (the latterbeing diagrammatically illustrated), and this. ligure indicates theposition of the craft at rest showing the floats 2 and?) as emersed andcarrying an appreciable portion of the Weight of the craft. Figs. 3-elshow the floats i3 and 3 as slightly removed or displaced in thedirection of the longitudinal axis of the crafty from the medianyposition thereof, whereby the tilting or inclination of the craft atstarting about the median portion thereof elevates the floats and causesthe emergence thereof prior to the emergence of the boat itself. lorexample, llig. Zlindicates the` position at startingvnivhen the doats2", 3 are emerging' from'they Water, the inclined or tilted position ofthe craft causing the elevation of the forwardly positioned doats andfacilitating the prior emergence thereof. rlhe center of pressure orbuoyancy of the float il', (3') is indicated as being approxi-4 matelyin the position 9 Whichis observed to be slightly forward of the centerof gravity of the craft approximately indicated at l0.. lWhile theforward shifting of the floats 2 and 3 `is the preferred arrangement. itis observed, as indicated above, that the advantages of the applicantsinvention may be attained by having the displacement floats simplysituated at a higher level than the boat body, but in this case forbestresults it is desirable that the displacement floats be arrangedapproximately midships of the boat hull, namely with their bowsextending forward of the center of gravity 10 of the craft.

l claim l. ln a. flying boat the combination of a main boat body ofsumcient dimensions and displacement to contain therewithin thepersonnel compartment and to buoyantly and hydro-dyna1nically supporttheV greater portion of the Weightof the craft,l with a pair of lateralsupporting displacement and 'hydroplaning floats disposed on 'oppositesides neoaeee of the boat body with their bovvs extending forward of toecenter f gravity of the boat and adapted to hydrostatically andhydrodynamica-lly support an appreciable portion of the Weight of thecraft, and a supporting structure positioning and dring the floatsrelatively to the boat so as to carry a definite and appreciable portionof the Weight of the craft at rest, and upon starting to exert apositive lifting force upon the craft up to a certain critical speed butto emerge from the water prior to the emergence of the boat..

it. flying boat of the character set forth in claim l wherein the sidedisplacement tioats are disposed in close proximity to the boat hull andtheir hydroplaning bottoms are disposed above the level of and entirelydisconnected from the boat bottom.

3. ln a flying boat a floating and hydroplaning structure including amain central elongated boat body and apair of separate and distinctlateral supporting displacement and hydroplaning floats arranged onopposite sides of said main central boat body and in close proximitythereto, said floats being supported by the craft in a manner to carryan` appreciable portion of the total Weight of the cra-ft boti While atrest and during the early sta. "es of the planing operation and havingtieir centers of pressure disposed slightly forvvard of the center ofgrav ity of the craft.

t flying boat of the character set forth in claim l wherein the sidedisplacement floats are disposed intermediate the ends of the boatstructure but displaced longitudi nelly of the boat from the medianposition thereof.

o .ln a hydro-aeroplane, the combination of i lifting plane, with afloating and hydroplaning structure thereunder including main centralboat body of sucient die placement to buoyantly and hydro-dynamicallysupport the greater portion of the Weight of the craft, a pair ofseparate and distinct lateral supporting displacement and hydroplaningfloats disposed on opposite sides of the central boat body with theirbows extending forward of the median position of the central boat body,said lateral floats being adapted to buoyantly and hydrodynamicallysupportyan appreciable portion of the Weight of the craft, and asupporting structure ositioning and fixing the side floats relatively tothe main central buoyant body so as to carry a definite and appreciableportion of the weight of the craft at rest and upon starting to exert apositive lifting force upon the craft up to a certain critical speed butto emerge from the Water prior to the emergence of the boat. s

6. ln a flying -boat alifti'ng Wing,A a power plant for-propelling thecraft during flight and a floating 'and'hyd'roplaning structurethereforincluding a main central boat body of suflicient displacement tobuoyantly and hydro-dynamically supportthe greater portion of the weightof the craft and a pair of separate and distinct lateral supportingdisplacement and hydroplaning floats disposed on opposite sides of themain central boat body and in close proximity thereto with their bowsextending forward of the median position of the boat body, said lateralfloats being supported by the craft in a-manner to carry an appreciableportion of the weight of the craft while floating at rest andhydroplaning at speeds below a predetermned value upon the water,whereby a large and positive metacentric height is obtained and theresistance to the propulsion through the water is caused tosubstantially decrease before the taking off speed is reached due to thelifting operation of the lateral floats and the inclination of the bowof the boat.

7. In a flying boat the combination of a main boat body with lateralsupporting displacement and hydroplaning floats disposed on oppositesides thereof, said floats being displaced slightly forward of themedian position of the boat and being supported in a manner to carry anappreciable portion of the weight of the craft while floating at restand to exert a lifting force on the boat while attaining a taking ofllspeed.

8. In a flying boat, the combination of a main boat body with a pair ofsupporting displacement and hydroplaning floats arranged on oppositesides thereof and with their bows extending forward of the medianposition of the boat, said floats being separate and distinct from theboat but being of a character and being supported in a manner to beimmersed when the boat is immersed and to carry an appreciable part ofthe weight of the craft in 'cooperation therewith but to clear the waterin advance of the boat during the taking ofi' operation.

9. A flying boat comprising a boat body in combination with a pair oflateral floats,

horizontal struts extending from the boat body' and connecting thefloats with vthe same, said struts being formed as axles on which wheelsmay be mounted, interchangey ably with the floats.

10. A flying boat of the character set forth in claim 8 wherein thelateral displacement and hydroplaning floats are ,braced both againstthe boat and the wings.

In testimony whereof I aiix my signature.

DR. ADOLF ROHRBACH.

